Hot-air furnace.



No. 652,297, Patented June 26, I900.

HOT AIR FURNACE.

(Application filed Feb. 3, 1900.) (No Modal.) 3 Shaets$haet l.

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In SMEAD HOT AIR FURNACE.

(Application filed Feb. 3, 1900.) (No Model.) 3 Sheets-$heot Z.

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UNITED STATES T ISAAC D. SMEAD, OF TOLEDO, OHIO.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No. 652,297, dated June 26, 1 900. Application filed February 3, 1900. Serial No. 3,846. (No model.)

T0 at whom, it may concern:

Be it known that I, ISAAC D. SMEAD, a citizen of the United States, residing at Toledo, in the county of Lucas and State of Ohio, have invented certain new and useful Improvements in Hot-Air Furnaces, of which the following is a specification.

My present invention relates to furnaces for warming buildings; and the invention consists in a novel construction of the furnace whereby the air to be warmed is first brought into contact with that part of the furnace which is the least heated and leaves it at the part most heated and whereby also the furnace is rendered more convenient to manage and to repair.

Figure 1 is a transverse vertical section on the line 2 2 of Fig. 3. Fig. 2 is a similar View on the line 3 3 of Fig. 3. Fig. 3 is a transverse horizontal section on the line 1 1 of Fig. 2-, and Fig. 4. is a perspective view with a portion broken away.

This invention relates to that class of furnaces ordinarily used for heating private residences, generally designated as pot-furnaces, the bodies of which are usually round, or nearly so, and are greater in height than in circumference.

One object of this invention is to provide a furnacein which the airto be heated shall first be brought into contact with that part of the furnace which is least heated and from thence pass gradually to a hotter portion and finally leave it at the hottest part.

Another object is to so construct it that it will be more convenient or easy to manage or take care of and also so that the fire-pot and grate can be readily withdrawn and replaced without taking the furnace apart, thus rendering it more easy to repair.

In all ordinary round or pot furnaces the fire-pot is usually placed at or near the botresult of such a construction is that the hottest portion of the body is near the bottom, and as the cold air enters at or near the bottom it follows that the air is first brought into contact with the hottest portion of the furnace and as it ascends is brought into contact with portions which are less hot, so that if the air be heated below to a temperature equal or nearly equal to that of the upper and (indicated in Fig. 3) to a projection P at the rear, to which the smoke-pipe II is attached, as shown in Figs. 1 and 2. Upon the plate a is mounted a series of vertical pipes J, connected at their top to an annular plate I), which is provided with openings and collars for that purpose, and upon this plate I) is placed the annular body A, which surrounds the fire-pot E, and on this body A is set the dome D, as clearly shown in Figs. 1 and 2. The upper plate 6 is arranged to receive a series of grate-bars g, which maybe of any suitable kind, and also 'thefire-pot E, which is thus supported within the upper portion of the furnace as near the top or dome as is practicable without rendering the dome too hot. Underneath the fire-pot is located a receptacle I for the reception of the ashes and cinders from the fire-pot and which maybe cast integral with the plate 6, as shown in Fig. 2, or separately, if preferred. At the bottom of this receptacle is another grate h, finer than the one above, so as to permit the passage of the ashes only, thereby retaining the cinders or fragments of unburned coal in the receptacle I, from whence they can be readily removed through the door Y at the front and be thrown back into the fire-pot and consumed. Underneath this receptacle I and within the chamber formed by the vertical plate L (shown in Figs. 1 and 2) is placed a pan or vessel G to receive the ashes sifted through the grate 7L,l]l1616 being a door through which this ash vessel can be removed when necessary.

The fire-pot E is made of the form of the letter U as shown in Fig. 3, and to enable it to be removed or replaced when necessary I provide a door W at the front of the full width of the fire-pot, so that by opening this door W the fire-pot can be drawn out or put in without disturbing any other portion. This door W is formed with an opening for introducing the fuel, and this opening is closed by a smaller door V, as shown in Figs. 1 and 3. This fueldoor V is provided with a slide to regulate the admission of air and has a perforated plate secured to it inside, and as this plate becomes highly heated the air passing through it is delivered heated in a series of jets, thereby greatly aiding the combustion of the fuel; but this perforated plate being a well-known device is not shown in the drawings. As shown in Figs. 2 and 3, the fire-pot is not bolted or in any manner secured to any other portion of the furnace, but simply rests on the transverse plate 1) and is therefore free to expand or contract without straining it or any of the other parts. The fire-pot is made of cast-iron in a single piece, and, as shown in Figs. 1 and 3, it has its bottom closed at the front by a transverse plate cast integral with the sides,so that the open part occupied by the grate-bars occupies a central position within the body A, and as there is a uniform space all around the fire-pot except at the front for the downward passage of the heat and products of combustion its walls will be so uniformly heated as to greatly lessen the liability of its being cracked by unequal expansion. The grate 9 consists of a series of rocking bars connected by pinions or gear-wheels, the ends of the grate-bars resting in recesses in the plate b,made for that purpose, as shown in Fig.

- 3, so that when the fire is drawn out the gratebars are free to be lifted out without the removal of any bolts or other parts. This method of construction, which enables the fire-pot and the grate to be removed and replaced at will without disturbing or disconnecting any of the other parts, is veryimportant, as these are the parts which usually require to be renewed. It will also be observed that the transverse plates 1", a, and b are provided with grooves into which the vertical parts fit and that the body A and dome D are united in the same manner, thus enabling the entire furnace to be put together without the use of any bolts and nuts, so troublesome to remove after they have become affected by the heat and rust.

The joints can of course be rendered gas-tight by the use of the proper cement when the parts are assembled.

In order to afford a direct draft for starting a fire, the body A is connected by a short pipet to the smoke-pipe H, this pipe 25 being provided with a damper s, which is to be closed after the fire is Well started, in order to cause the products of combustion to descend through the pipes J into the annular chamber T in the base and from thence through the rear projection P into the smokepipe H, as indicated by the arrows in Fig. 1.

The furnace proper is inclosed within a sheet-iron case N, from the top of which the hot-air pipes extend in the usual manner, the transverse plate 1 being made of the proper heat throughout its entire passage.

diameter and provided with grooves to receive and hold this inclosing shell or case, as shown in Figs. 1 and 2. At the base two or more clean-out doors 2 are made in this outer shel1,with corresponding doors 6 opening into the annular chamber T in the base, through which the ashes and soot can be removed whenever necessary. This plate 1" is also provided with holes or oblong openings through which the air to be heated and which enters at the bottom passes upward between the furnace proper and its casing.

By the construction and arrangement of the fire-pot at the top it will be seen that the air entering at the bottom is first brought into contact with the coolest portion of the furnace, and as it ascends it is in contact with a constantly-increasing hotter portion, until finally it reaches the dome, which is hottest of all, and by this means is made to absorb Another advantage of this constructionis that it enables the attendant to look into the fire-box, replenish the fuel, and remove the cinders or unburned coal without stooping,.as is necessary with furnaces having the fire-pot located at or near the bottom.

Having thus fully described my invention, what I claim is- 1. The combination in a furnace of the annular body A, and the removable U-shaped fire-pot E of such a size and form as to leave a space at the sides and rear for the passage between it and the body, of the products of combustion, said fire-pot being located in the upper portion of the body, substantially as and for the purpose described.

2. A furnace having a fire-pot consisting of the U shaped body or side walls and a bot tom plate at the front end cast integral, a support for said fire-pot so shaped that the firepot maybe inserted and removed bodily without detaching or removing any other part.

3. As a new article of manufacture, a furnace consisting of the annular body A provided near its top with the door W for the removal of the fire-pot with the fuel-door V mounted in the door W, the diaphragm 1) arranged to support the fire-pot and the grate g, with the smoke-fines J extending from the diaphragm b downward to the annular chamber T at the base, and having a cinder-receptacle I underneath the fire-pot, and below that a chamber for the ash receptacle or vessel G, all constructed and arranged to operate substantially as shown and described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ISAAC I). SMEAD.

Witnesses:

EARLE S. BURNETT, ANTHONY KUEFER. 

